The vertical velocity at the top of Ekman layer caused by katabatic winds is proposed and deduced. By computing actual data we get a distribution of the velocities over Antarctica. The distribution plays a positive ro...The vertical velocity at the top of Ekman layer caused by katabatic winds is proposed and deduced. By computing actual data we get a distribution of the velocities over Antarctica. The distribution plays a positive role in maintaining the cyclone and anticyclone over Antarctica.展开更多
The West African Monsoon (WAM) is characterized by strong decadal and multi-decadal variability and the impacts can be catastrophic for the local populations. One of the factors put forward to explain this variability...The West African Monsoon (WAM) is characterized by strong decadal and multi-decadal variability and the impacts can be catastrophic for the local populations. One of the factors put forward to explain this variability involves the role of atmospheric dynamics, linked in particular to the Saharan Heat Low (SHL). This article addresses this question by comparing the sets of preindustrial control and historical simulation data from climate models carried out in the framework of the CMIP5 project and observations data over the 20<sup>th</sup> century. Through multivariate statistical analyses, it was established that decadal modes of ocean variability and decadal variability of Saharan atmospheric dynamics significantly influence decadal variability of monsoon precipitation. These results also suggest the existence of external anthropogenic forcing, which is superimposed on the decadal natural variability inducing an intensification of the signal in the historical simulations compared to preindustrial control simulations. We have also shown that decadal rainfall variability in the Sahel, once the influence of oceanic modes has been eliminated, appears to be driven mainly by the activity of the Arabian Heat Low (AHL) in the central Sahel, and by the structure of the meridional temperature gradient over the inter-tropical Atlantic in the western Sahel.展开更多
We present preliminary results from the experimental investigation of the response of the atmosphere due to the impact of powerful shock waves. The response is evidenced as ultra low frequency electromagnetic wave rad...We present preliminary results from the experimental investigation of the response of the atmosphere due to the impact of powerful shock waves. The response is evidenced as ultra low frequency electromagnetic wave radiation at frequency of 2-5 kHz and in duration of 3 7s. We hypothesize that this radiation appears due to the following process： the shock wave ionizes the neutral particles in the air and these charged and neutral particles continue their vertical motion, which forms in the trail of the shock wave. Such motion can cause the cyclotron-like radiation measured.展开更多
Mixed metal oxides in the nanoscale are of great interest for many aspects of energy related research topics as water splitting, fuel cells and battery technology. The development of scalable, cost-efficient and robus...Mixed metal oxides in the nanoscale are of great interest for many aspects of energy related research topics as water splitting, fuel cells and battery technology. The development of scalable, cost-efficient and robust synthetic routes toward well-defined solid state structures is a major objective in this field.While monometallic oxides have been studied in much detail, reliable synthetic recipes targeting specific crystal structures of mixed metal oxide nanoparticles are largely missing. Yet, in order to meet the requirements for a broad range of technical implementation it is necessary to tailor the properties of mixed metal oxides to the particular purpose. Here, we present a study on the impact of the nature of the gas environment on the resulting crystal structure during a post-synthesis thermal heat treatment of manganese–cobalt oxide nanoparticles. We monitor the evolution of the crystal phase structure as the gas atmosphere is altered from pure nitrogen to synthetic air and pure oxygen. The particle size and homogeneity of the resulting nanoparticles increase with oxygen content, while the crystal structure gradually changes from rocksalt-like to pure spinel. We find the composition of the particles to be independent of the gas atmosphere. The manganese–cobalt oxide nanoparticles exhibited promising electrocatalytic activity regarding oxygen evolution in alkaline electrolyte. These findings offer new synthesis pathways for the direct preparation of versatile utilizable mixed metal oxides.展开更多
Based on the tide gravity observations recorded with LCR-ET20 spring gravimeter at Wuhan international fundamental tidal gravity station, the characteristics of ET20 and atmospheric and oceanic gravity signals are stu...Based on the tide gravity observations recorded with LCR-ET20 spring gravimeter at Wuhan international fundamental tidal gravity station, the characteristics of ET20 and atmospheric and oceanic gravity signals are studied systematically by using international standard data pre-processing and analysis methods and by comparing the results with those obtained by superconducting gravimeter (SG) at the same station. The numerical results indicate that the identical tidal gravity parameters are the same as those with the SG, the instrument can be effectively used to record temporal change of the gravity field, though the ET20 accuracy is one order lower than that of the SG, and has the large drift induced by the spring creep character.展开更多
Es werden nach neuen Beobachtungen und Arbeitenüber die Meeresstro-mungen im allgemeinen und in den einzelnen Ozeanensowie ihre Schichtung und Tiefenzirkulation besprochen.Dies wird in vier Abschnitten geteilt:(1...Es werden nach neuen Beobachtungen und Arbeitenüber die Meeresstro-mungen im allgemeinen und in den einzelnen Ozeanensowie ihre Schichtung und Tiefenzirkulation besprochen.Dies wird in vier Abschnitten geteilt:(1)Atmosphärische Einfluisse an der Meeresoberfläsche und dadurch hervorgerufene Meeresstromungen,(2)Die ozeanische Troposphare und die ozeanische Stratosphare,(3)Die troposiphÃrischen Strömungen der einzelnen Ozeane,(4)Die stratosphÃrische Zirkulation im allgemeinen und in den Ozeanen.展开更多
文摘The vertical velocity at the top of Ekman layer caused by katabatic winds is proposed and deduced. By computing actual data we get a distribution of the velocities over Antarctica. The distribution plays a positive role in maintaining the cyclone and anticyclone over Antarctica.
文摘The West African Monsoon (WAM) is characterized by strong decadal and multi-decadal variability and the impacts can be catastrophic for the local populations. One of the factors put forward to explain this variability involves the role of atmospheric dynamics, linked in particular to the Saharan Heat Low (SHL). This article addresses this question by comparing the sets of preindustrial control and historical simulation data from climate models carried out in the framework of the CMIP5 project and observations data over the 20<sup>th</sup> century. Through multivariate statistical analyses, it was established that decadal modes of ocean variability and decadal variability of Saharan atmospheric dynamics significantly influence decadal variability of monsoon precipitation. These results also suggest the existence of external anthropogenic forcing, which is superimposed on the decadal natural variability inducing an intensification of the signal in the historical simulations compared to preindustrial control simulations. We have also shown that decadal rainfall variability in the Sahel, once the influence of oceanic modes has been eliminated, appears to be driven mainly by the activity of the Arabian Heat Low (AHL) in the central Sahel, and by the structure of the meridional temperature gradient over the inter-tropical Atlantic in the western Sahel.
文摘We present preliminary results from the experimental investigation of the response of the atmosphere due to the impact of powerful shock waves. The response is evidenced as ultra low frequency electromagnetic wave radiation at frequency of 2-5 kHz and in duration of 3 7s. We hypothesize that this radiation appears due to the following process： the shock wave ionizes the neutral particles in the air and these charged and neutral particles continue their vertical motion, which forms in the trail of the shock wave. Such motion can cause the cyclotron-like radiation measured.
基金supported by the Federal Ministry of Education and Research under the grant reference number 03SF0433A "MEOKATS"
文摘Mixed metal oxides in the nanoscale are of great interest for many aspects of energy related research topics as water splitting, fuel cells and battery technology. The development of scalable, cost-efficient and robust synthetic routes toward well-defined solid state structures is a major objective in this field.While monometallic oxides have been studied in much detail, reliable synthetic recipes targeting specific crystal structures of mixed metal oxide nanoparticles are largely missing. Yet, in order to meet the requirements for a broad range of technical implementation it is necessary to tailor the properties of mixed metal oxides to the particular purpose. Here, we present a study on the impact of the nature of the gas environment on the resulting crystal structure during a post-synthesis thermal heat treatment of manganese–cobalt oxide nanoparticles. We monitor the evolution of the crystal phase structure as the gas atmosphere is altered from pure nitrogen to synthetic air and pure oxygen. The particle size and homogeneity of the resulting nanoparticles increase with oxygen content, while the crystal structure gradually changes from rocksalt-like to pure spinel. We find the composition of the particles to be independent of the gas atmosphere. The manganese–cobalt oxide nanoparticles exhibited promising electrocatalytic activity regarding oxygen evolution in alkaline electrolyte. These findings offer new synthesis pathways for the direct preparation of versatile utilizable mixed metal oxides.
基金National Outstanding Youth Foundation of China (49925411) the Knowledge Innovation Foundation,Chinese Academy of Sciences (KZCX2-SW-131).
文摘Based on the tide gravity observations recorded with LCR-ET20 spring gravimeter at Wuhan international fundamental tidal gravity station, the characteristics of ET20 and atmospheric and oceanic gravity signals are studied systematically by using international standard data pre-processing and analysis methods and by comparing the results with those obtained by superconducting gravimeter (SG) at the same station. The numerical results indicate that the identical tidal gravity parameters are the same as those with the SG, the instrument can be effectively used to record temporal change of the gravity field, though the ET20 accuracy is one order lower than that of the SG, and has the large drift induced by the spring creep character.
文摘Es werden nach neuen Beobachtungen und Arbeitenüber die Meeresstro-mungen im allgemeinen und in den einzelnen Ozeanensowie ihre Schichtung und Tiefenzirkulation besprochen.Dies wird in vier Abschnitten geteilt:(1)Atmosphärische Einfluisse an der Meeresoberfläsche und dadurch hervorgerufene Meeresstromungen,(2)Die ozeanische Troposphare und die ozeanische Stratosphare,(3)Die troposiphÃrischen Strömungen der einzelnen Ozeane,(4)Die stratosphÃrische Zirkulation im allgemeinen und in den Ozeanen.
